PMDF System Manager's Guide

A substitution of the form $]ldap-url[ is handled specially. ldap-url is interpreted as an LDAP query URL and the result of the LDAP query is substituted. Standard LDAP URLs are used, with the host and port omitted; the host and port are instead specified with the LDAP_HOST and LDAP_PORT PMDF options (see Section 7.3.2 for further discussion of this option). That is, the LDAP URL should be specified as

ldap:///dn[?attributes[?scope?filter]]

where the square bracket characters [ and ] shown above indicate optional portions of the URL. The dn is required and is a distinguished name specifying the search base. The optional attributes, scope, and filter portions of the URL further refine what information to return. For a rewrite rule, the desired attributes to specify returning might be a mailRoutingSystem attribute (or some similar attribute). The scope may be any of base (the default), one, or sub. And the desired filter might be to request the return of the object whose mailDomain value matches the domain being rewritten.

For instance, at a site example.com with an LDAP server running on port 389 of the system ldap.example.com, the PMDF option file might have the lines

LDAP_HOST=ldap.example.com LDAP_PORT=389

set, and if the LDAP directory schema includes attributes mailRoutingSystem and mailDomain, then a possible rewrite rule to determine to which system to route a given sort of address might appear as:

.example.com \ $U%$H$D@$]<ldap:///o=example.com?mailRoutingSystem?sub?(mailDomain=$D)[

where here the LDAP URL substitution sequence $D is used to substituted in the current domain name into the LDAP query constructed; for ease in reading, the backslash character, \, is used to continue the single logical rewrite rule line onto a second physical line. See Table 3-1 for a full list of the LDAP URL substitution sequences available.